3种不同培养基对斜生栅藻生长和油脂积累的影响

以斜生栅藻FACHB-12为原料,采用BG11、F/2和SE 3种培养基对其培养。通过对生物量、生长速率、油脂含量、油脂组分以及脂肪酸组成的测定,比较不同培养基对斜生栅藻生长和油脂积累的影响。结果表明:BG11培养基更有利于斜生栅藻的生长,而F/2培养基更适合油脂以及中性脂的积累;斜生栅藻在BG11培养基中比生长速率为0.095,培养15 d生物量为0.36 g/L,叶绿素a含量达到1.23 mg/L;而在F/2培养基中油脂含量可达细胞干重的24.75%,其中中性脂占总脂的36.64%,产率达0.98 mg/(L·d);并且在F/2培养基中斜生栅藻脂肪酸组成以C16∶0和C18∶1为主,含量分别占总脂肪酸的25.84%和54.47%,更适合作为制备生物柴油的原料。     

水杨酸诱导对斜生栅藻生长及油脂积累的影响

为缓解化石能源压力,提高生物质能源的使用率,以空气中CO₂作为自养培养斜生栅藻的碳源,添加植物激素水杨酸(SA)诱导斜生栅藻,研究斜生栅藻细胞密度、叶绿素a含量、油脂含量及产率等的变化情况,探讨在SA诱导下斜生栅藻的产脂机制。结果表明：培养16 d, SA对斜生栅藻生长及油脂积累表现出显著促进效果,当SA质量浓度为20 mg/L时,细胞密度最大,为(1.89±0.06)g/L,较对照组提高了34.47%;在实验范围内(SA质量浓度0～40 mg/L),油脂产率与SA质量浓度呈线性正相关;油脂含量及产率均在SA质量浓度为40 mg/L时达到最大,分别为(48.49±7.47)%和(22.35±3.77)mg/(L·d),较对照组分别提高了72.85%和1.43倍;SA对斜生栅藻细胞官能团中的酯基、羧基、磷酸基团等产生了影响;同时,在SA诱导下斜生栅藻的油脂代谢途径与叶绿素、酶、抗逆性等因素有关。综上,SA既提高了斜生栅藻的生物量,又促进了其光合作用和储能物质转化,提高了油脂产率。     

黄腐酸对Haematococcus pluvialis LUGU虾青素积累和lcy基因表达量的影响

雨生红球藻是虾青素的主要来源,为探明黄腐酸(FA)对雨生红球藻Haematococcus pluvialis LUGU的影响,将不同质量浓度的FA添加至对数生长期的藻液中置于胁迫条件下培养,并分别对细胞生物量浓度、虾青素积累质量浓度以及番茄红素β-环化酶(lcy)基因表达量进行了测定。结果表明,黄腐酸质量浓度为10 mg/L,藻细胞的生物量产率达到最大80.28 mg/(L·d),比对照组提高5.44%;而虾青素最大质量浓度为20.82 mg/L,是在FA质量浓度为5 mg/L时测得,比对照组提高了86.89%。RT-PCR分析显示,虾青素合成的关键基因lcy的表达受FA的影响,当添加5 mg/L和10 mg/L的黄腐酸时lcy基因最大的表达量分别为对照的1.2倍和0.7倍。实验证明FA诱导下的雨生红球藻虾青素的积累含量和lcy基因表达量呈正相关。     

外源乙烯利对雨生红球藻中虾青素积累的影响

本实验初步研究了一定浓度范围的乙烯利对雨生红球藻积累虾青素的影响。在对数生长期的藻液中分别加入一系列不同浓度的乙烯利溶液,然后转入胁迫培养(25℃,24h5000lux连续光照+营养盐饥饿),诱导细胞内虾青素的合成积累。在诱导过程中显微观察不同浓度乙烯利处理后细胞形态和色素积累的变化,并定期取样进行虾青素含量的测定。结果表明,添加0.05ml/L的乙烯利可以促进雨生红球藻积累虾青素,处理后的藻细胞比对照组的藻细胞提前17d完全变红,虾青素产量比对照提高了92.1%,达18.6mg/L藻液。另外还发现0.1ml/L的乙烯利对雨生红球藻积累虾青素有明显的抑制作用。高浓度的乙烯利(≥0.15ml/L)处理对雨生红球藻细胞存在致死作用。     

培养条件对眼点拟微绿球藻油脂含量和EPA产率的影响

眼点拟微绿球藻(N.oculata)具有生长速度快、含油量高等优点,且其脂肪酸组成中含有大量二十碳五烯酸(EPA),因此它是微藻生物柴油的良好原料。以眼点拟微绿球藻为对象,研究了培养时间、盐度、pH值等培养条件对眼点拟微绿球藻油脂含量和EPA产率的影响。试验表明:选择稳定5 d为眼点拟微绿球藻的最佳采收时间,油脂含量为378.1 mg/g干藻,EPA产率为5.5 mg/(L·d);当盐度为16.7时,眼点拟微绿球藻的油脂含量和EPA产率均能达到最高,油脂含量为506.0 mg/g干藻,EPA产率为7.37 mg/(L·d);在适合眼点拟微绿球藻生长的pH值(8.0~10.0)下,保持整个培养过程中pH值为8.0,油脂含量和EPA产率均较高,油脂含量为471.7 mg/g干藻,EPA产率为7.45 mg/(L·d)。     

氮、磷对单针藻异养生长与油脂合成的影响

在异养条件下,应用Andrew方程考察了氮、磷营养盐对单针藻Monoraphidium sp.FXY-10生长的影响,并研究了氮、磷营养盐对单针藻油脂含量的影响。结果表明,磷的半饱和常数(KS,P)小于氮的半饱和常数(KS,N),说明磷对单针藻生长的影响大于氮。此外,在NaNO3质量浓度为1 g/L时,生物量产率(253.77 mg/(L·d))、油脂产率(110.36 mg/(L·d))、油脂含量(43.49%)达到最大值;在K2HPO4质量浓度为0.1 g/L时,生物量产率(323.54 mg/(L·d))、油脂产率(136.83 mg/(L·d))、油脂含量(42.29%)达到最大值。并且在氮、磷缺乏的情况下,油脂含量相对较高。     

雨生红球藻和小球藻间的原生质体融合与糖异养融合子筛选

为了增强雨生红球藻的异养生长能力,提高规模化培养效率,本研究基于PEG介导的原生质体融合技术,在雨生红球藻SCCAP K-0084和小球藻SAG211.11a间开展了细胞融合以及糖异养融合子筛选研究,筛选中通过限制性糖异养条件和添加潮霉素分别抑制野生型的雨生红球藻和小球藻的生长,提高筛选效率。结果表明,小球藻SAG211.11a具有极强的异养生长能力,能够利用葡萄糖、果糖、乙酸钠、甘油、苹果酸以及琥珀酸进行异养生长,而雨生红球藻则仅能够利用乙酸盐进行异养生长,此外雨生红球藻SCCAP K-0084还具有极强的潮霉素耐受能力,可以被应用于融合子筛选中。研究中,雨生红球藻和小球藻的原生质体制备效率分别达到72.11%±3.94%和42.07%±3.73%,满足细胞融合需要,融合过程中观察到雨生红球藻和小球藻间的典型融合现象,并且在限制性糖异养筛选下获得了雨生红球藻形态的融合子克隆,融合子的生长速率相比于野生型雨生红球藻有明显的增强,三个融合子在10 d培养后细胞密度分别达到6.7×10~4、8.7×10~4、6.5×10~4个/mL,明显高于野生型的2.45×10~4个/mL,但是相比于小球藻10 d后1.4×10~6个/mL的细胞密度而言,异养生长能力仍然有限,而且在连续传代过程中融合子经常会出现表型分化的现象。这一研究证明,通过细胞融合杂交的方式能够使雨生红球藻获得糖异养的生长能力,但是异源基因组间重组效率有待进一步提高。     

利用控pH流加培养法提高雨生红球藻的生物量及虾青素产量

研究了一种新型培养方法——控pH流加培养法,可有效促进雨生红球藻生长并提高虾青素产量。测定雨生红球藻生长期间对营养盐的需求量,依据对数生长期藻液pH与硝酸盐和磷酸盐的含量的线性关系,确定流加液组成及流加方法。流加液的组成为7.88 g/L的KNO3,1.83 g/L的KH_2PO_4和24.0 g/L的CH_3COONa,监测对数生长期藻液pH变化情况,通过添加流加液将藻液的pH值持续控制在7.5~8.0内,雨生红球藻的细胞干重可达(1.42±0.04)g/L,虾青素产量可达(60.23±1.81)mg/L。     

雨生红球藻等离子诱变及高产藻株的筛选

目的通过等离子体诱变筛选获得高产虾青素的雨生红球藻突变株。方法将常压室温等离子体应(atmospheric and room temperature plasma,ARTP)用于雨生红球藻的诱变育种处理。ARTP在常温下以输入功率100 W、处理距离2mm、气体流速10 L/min处理雨生红球藻40s,雨生红球藻的致死率达90%以上。在此条件下获得诱变株后,以虾青素合成抑制剂作为筛选剂,成功筛选获得一株虾青素高产藻株M45。结果该突变株的生物量和生长速率分别较出发株提高了6.45%和8.57%。突变株M45的虾青素含量达3.1%,较出发株提高了51.96%;虾青素产量为71.92 mg/L,相比于出发株提高了61.73%,且遗传稳定性实验表明,M45生产性能稳定。结论经等离子体诱变获得的突变株M45虾青素含量高,生产性能稳定,具有一定的工业应用前景,等离子体诱变方法适用于雨生红球藻的育种。     

不同温度下雨生红球藻优良藻株筛选

为获得适宜大规模培养的藻株,研究和比较了雨生红球藻(Haematococcus pluvialis)3个不同品系分别在15、20、25、30℃中的生长和虾青素积累情况。结果表明,温度对雨生红球藻的生长和虾青素积累有显著的影响,并且与藻种品系有关。各培养温度下,雨生红球藻藻株H3的细胞密度、藻细胞干重、虾青素含量和产量具有明显优势。藻株H3的最适生长温度为15℃,其最终细胞密度和细胞干重分别为11.75×10~4 cell/mL和0.337 g/L,但该条件不利于虾青素的积累;虾青素积累在20℃培养时最高,其虾青素含量和产量分别为1.15%、3.41 mg/L;而在30℃时生物量和虾青素产量均最低。因此,优先选择H3作为大规模培养的藻种。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the